Turkey's government announced Friday that at least 682 inmates were participating in a hunger strike in at least 67 prisons across the country, but it insisted that no protesters were in critical condition.

The statement by Turkey's Justice Ministry directly contradicted reports issued by members of two opposition parties.

Dr. Aytug Atici, a medical doctor and a lawmaker from the secularist Republican People's Party, told CNN that prisoners he met during a tour of detention facilities were starting to lose basic brain functions and were showing symptoms of starvation.

"None of the people who have been on strike for 50 days, at the time when we spoke to them (Wednesday), could stand," Atici said in a phone interview with CNN. "They have begun to bleed anally and nasally. They are in critical condition."

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The maximum weight loss of protesters at one prison, the ministry reported, was 8 kilograms (about 18 pounds), though it said that it was impossible to determine weight loss with some detainees because they "refused to be weighed."

The hunger strike began more than a month ago, and has since spread throughout Turkey's penal system.

Most, if not all, of the protesters are ethnic Kurds. Their demands, according to officials from the Peace and Democracy Party -- Turkey's largest and best-organized Kurdish nationalist party -- are twofold: permission to use the Kurdish language in education and in courtrooms, and an end to the solitary confinement and eventual liberation of Abdullah Ocalan.

Ocalan is the jailed founder of the Kurdistan Workers' Party, or PKK. The movement has been fighting a guerrilla war against the Turkish state for 30 years. Turkey, the U.S. and the EU officially label the PKK a terrorist organization.

The hunger strike comes against a backdrop of steadily worsening PKK violence. According to a report published last September by the nonprofit conflict mediation organization International Crisis Group, the violence has killed more than 700 people in a 14-month period.

"There is no hunger strike or anything. It's a show," Recep Tayyip Erdogan said in a statement before journalists during a visit to Berlin on Wednesday. He went on to suggest that the PKK had ordered the protesters to starve themselves.

The prison hunger strike is a phenomenon that harkens back to turbulent past decades of Turkish modern history. It was a protest measure used by leftists and communists in the 1990s and at the turn of the century that left scores of people dead.

"When we think about hunger strikes, we always think about people getting killed," said Mehmet Ali Birand, a veteran journalist and anchor on Turkish television.

"I remember at that time in 1996 and 2000, public opinion was very much against the government's handling of the situation," he added. "But this time ... public opinion is not buying it ... they are not looking favorably at the hunger strikers."

On Friday, Turkey's semiofficial Anatolian Agency reported another fatality in the long-simmering PKK conflict, which has claimed more than 30,000 lives over the last three decades.

The news agency said that at least one soldier was killed and six wounded during a suspected PKK attack on a post in southeastern Turkey on Friday.